Commit f6db8347 authored by Naveen N. Rao's avatar Naveen N. Rao Committed by Ingo Molnar
Browse files

sched/stat: Simplify the sched_info accounting dependency 



Both CONFIG_SCHEDSTATS=y and CONFIG_TASK_DELAY_ACCT=y track task
sched_info, which results in ugly #if clauses.

Simplify the code by introducing a synthethic CONFIG_SCHED_INFO
switch, selected by both.

Signed-off-by: default avatarNaveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: a.p.zijlstra@chello.nl
Cc: ricklind@us.ibm.com
Link: http://lkml.kernel.org/r/8d19eef800811a94b0f91bcbeb27430a884d7433.1435255405.git.naveen.n.rao@linux.vnet.ibm.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 407a2c72

include/linux/sched.h

+3 −3
Original line number Diff line number Diff line
@@ -849,7 +849,7 @@ extern struct user_struct root_user; 
struct backing_dev_info;

struct reclaim_state;



#if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)

#ifdef CONFIG_SCHED_INFO

struct sched_info {

	/* cumulative counters */

	unsigned long pcount;	      /* # of times run on this cpu */
@@ -859,7 +859,7 @@ struct sched_info { 
	unsigned long long last_arrival,/* when we last ran on a cpu */

			   last_queued;	/* when we were last queued to run */

};

#endif /* defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT) */

#endif /* CONFIG_SCHED_INFO */



#ifdef CONFIG_TASK_DELAY_ACCT

struct task_delay_info {
@@ -1408,7 +1408,7 @@ struct task_struct { 
	int rcu_tasks_idle_cpu;

#endif /* #ifdef CONFIG_TASKS_RCU */



#if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)

#ifdef CONFIG_SCHED_INFO

	struct sched_info sched_info;

#endif

init/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -435,6 +435,7 @@ config TASKSTATS 
config TASK_DELAY_ACCT

	bool "Enable per-task delay accounting"

	depends on TASKSTATS

	select SCHED_INFO

	help

	  Collect information on time spent by a task waiting for system

	  resources like cpu, synchronous block I/O completion and swapping

kernel/sched/core.c

+1 −1
Original line number Diff line number Diff line
@@ -1975,7 +1975,7 @@ int sched_fork(unsigned long clone_flags, struct task_struct *p) 
	set_task_cpu(p, cpu);

	raw_spin_unlock_irqrestore(&p->pi_lock, flags);



#if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)

#ifdef CONFIG_SCHED_INFO

	if (likely(sched_info_on()))

		memset(&p->sched_info, 0, sizeof(p->sched_info));

#endif

kernel/sched/stats.h

+2 −2
Original line number Diff line number Diff line
@@ -47,7 +47,7 @@ rq_sched_info_depart(struct rq *rq, unsigned long long delta) 
# define schedstat_set(var, val)	do { } while (0)

#endif



#if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)

#ifdef CONFIG_SCHED_INFO

static inline void sched_info_reset_dequeued(struct task_struct *t)

{

	t->sched_info.last_queued = 0;
@@ -156,7 +156,7 @@ sched_info_switch(struct rq *rq, 
#define sched_info_depart(rq, t)		do { } while (0)

#define sched_info_arrive(rq, next)		do { } while (0)

#define sched_info_switch(rq, t, next)		do { } while (0)

#endif /* CONFIG_SCHEDSTATS || CONFIG_TASK_DELAY_ACCT */

#endif /* CONFIG_SCHED_INFO */



/*

 * The following are functions that support scheduler-internal time accounting.

lib/Kconfig.debug

+5 −0
Original line number Diff line number Diff line
@@ -841,9 +841,14 @@ config SCHED_DEBUG 
	  that can help debug the scheduler. The runtime overhead of this

	  option is minimal.



config SCHED_INFO

	bool

	default n



config SCHEDSTATS

	bool "Collect scheduler statistics"

	depends on DEBUG_KERNEL && PROC_FS

	select SCHED_INFO

	help

	  If you say Y here, additional code will be inserted into the

	  scheduler and related routines to collect statistics about

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